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Re: [seleukids] RE: Julian equivalents....

Dear Friends, I hope my enquiry of 23 April 2008 did not inconvenience anyone on this list. I was hoping that someone could direct me to an observed Babylonian

Message 1 of 4
, May 6, 2008

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Dear Friends,

I hope my enquiry of 23 April 2008 did not inconvenience anyone on this list. I was hoping that someone could direct me to an observed Babylonian eclipse (solar or lunar) or a verifiable lunar position close to those dates to enable me to decide their accurate Julian equivalents. I have not found anything useful and believe that lack of response to my original enquiry implies that you too found nothing worth reporting.

Unfortunately, by their nature, lunar dates are pretty useless because they prevent us from working out their Julian equivalents and establishing the precise moment of a past event. Modern computations have an accuracy of ±1 day which is very good for most, but not all, occasions.

Ancient users of Babylonian records from before their own times faced the same problems although the majority of them cared little about the accurate moments of past events. Just a rough idea about the number of elapsed "years" and some months might have been sufficient in almost every occasion but one, astronomy. Both Babylonian and non-Babylonian astronomers using Babylonian records required accurate dates of earlier astronomical phenomena. Simply some years and a few months or days was not good enough. That is why the Babylonian astronomers meticulously kept the length of their individual months: They began registering the events of each month by recording the length of the previous month, either 29 or 30 days. So, the later users could quickly add up the number of days and work out the "precise" moment of an earlier event. The reason for my writing "precise" is that even though the scribes took great care in maintaining accuracy, because they too were humans, occasional errors crept in. That is why we note sporadic discrepancies (no more than 1 day) between the length of the same month from the same year in different Babylonian astronomical records. However, in most cases such errors were compensated automatically since the Babylonian months were either 29 or 30 days long. So, for example, if a previous or current month was mistakenly given as 29 rather than 30 day, a near future 29-day month would have become 30 days long. This implies that long runs of successive Babylonian months ought to have had exactly the same number of days as the correct series of such months. Unfortunately (and in some cases, fortunately) this is not so. Even long sequences of Babylonian months could yield a ±1 or even ±2 days error in the total number of elapsed days. Naturally, later users of the Babylonian astronomical records would have had no way of verifying the exact number of days in earlier lunar months and so had to rely on the material at their disposal.

One such record, giving a long run of month-lengths (as well as some other data) is the Lunar Text 39 in Professor Hunger's volume 5 of the Astronomical and Related Texts from Babylon (2001), pp. 100-109. Originally, it contained information on the length of months as well as some lunar data for the period 62-93 SEB and also data concerning solstices, equinoxes, and Sirius for 62-69 SEB. Unfortunately, the tablet has suffered some damage, but the majority of the original information is still intact.

This and similar tablets must have been compiled to provide a "quick reference" for future astronomers to work out the elapsed number of days between an earlier and current event quickly. They then used this information in predicting some future events in advance.

The same tablets might well have been used by the non-Babylonian astronomers who visited Babylon in search of valuable data not to be found anywhere else in the ancient world. There can be little doubt that while on his visit to Babylon to obtain astronomical data to test his newly developed theories, Hipparchus required to compute the total number of days from a past astronomical event to his own time in order to be able to adapt the Babylonian lunar dates to a schematic astronomical calendar such as those used by Meton and Callipus a few centuries earlier. The fact that Hipparchus used long lists of Babylonian month-lengths can readily be shown by the slight error in at least one of the three records from the time of Seleucus II (246-225 BC) quoted in the Almagest. These are dated 67, 75 and 82 SEB.

Having worked out the exact Julian date of day 1 of one of the months in these records, I have shown that it is visibly different from that obtained from the corresponding Almagest date.

Hipparchus (or an equally competent non-Babylonian astronomer) certainly needed and indeed used long lists of Babylonian month-lengths like the one contained in the Lunar Text 39 (probably compiled under Antiochus III). Otherwise he would not have been able to transpose to a schematic astronomical calendar the purely Babylonian lunar dates from a century earlier, exactly as we failed to work out the Julian (= solar) equivalents of the dates I listed in my earlier post.

So, the unprecedented Seleucid dates in the Almagest, combining Macedonian months and SEB years, are simply the products from transposing the original Babylonian dates to a schematic astronomical calendar (with no fixed era and first calendar month) that could be adapted to any situation so long as the total number of days from a past event to the time of conversion could be computed. And we have the Lunar Text 39 and other tablets listing Babylonian month-lengths to show that the latter could easily have been achieved.

Of course, the above is simply a summary of my recent analysis of the Babylonian dates of the Seleucid period. I have purposely left out the evidence and its treatment in showing the discrepancy between the original Babylonian date and its later translation in the Almagest because they are not relevant to this list. I have, nevertheless, included the supporting material in a two-part note on the Babylonian, Seleucid and Parthian calendars that I hope to get published in the near future.

Is it possible to work out the Julian equivalents of the following three dates without using one (or more) of the currently available computer programmes and/or the Parker and Dubberstein (or similar) tables that give the Julian dates of the beginning of Babylonian months during 626 BC - AD 75?:

Dear Dr Assar, I am unable to assist you in your original inquiry. I am responding only because I would like to make sure that I correctly understand the

Message 2 of 4
, May 7, 2008

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Dear Dr Assar,
I am unable to assist you in your original inquiry. I am responding only because I would like to make sure that I correctly understand the apparent evolution in your thinking about the nature of the Chaldean dates.
In the past you have, more than vigorously, argued that these dates are representations of Babylonian astronomical dates made by some translator who was ignorant of the correct relationship between the Babylonian and Macedonian civil calendars in Seleucid times, which, in your view at that time, was already based on the Dios = Arahsamnu alignment which you have demonstrated for Parthian times. You held that this mis-translation was made long after the event and probably at some provincial site whence it came eventually to Ptolemy in Alexandria.
If I understand you correctly, from this post and from your recent posts on the HASTRO-L list, it is now your view that the translation was actually made in Babylon after all, very possibly by Hipparchus himself but in any case by a non-Babylonian astronomer (though I am unclear what exactly you mean by "translation" because you objected when I inferred on HASTRO-L that you thought Hipparchus was able to read cuneiform or Aramaic). I also understand that you now think the translation is not just a misrepresentation of a Babylonian date but involved a conversion to an independent Macedonian astronomical calendar, one in which the epoch of the day was not at dusk, which had no epoch for the year, and no defined era, presumably adopting the SEB year for convenience. Does that correctly reflect your current position?
Is it still your view that the Seleucid civil alignment was based on Dios = Arahsamnu in the third century and/or in Hipparchus' time? If so, how do you now explain the Dios = Tashritu alignment of these dates?
For the avoidance of doubt: I do not intend to debate the matter with you, in light of past experience. I only want to be sure I correctly understand your current position.
Regards,
Chris Bennett

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G.R.F. Assar

Dear Chris, If I had the opportunity to talk to you face to face, rather than being asked to explain my views in writing, I would have clarified the persisting

Message 3 of 4
, May 7, 2008

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Dear Chris,

If I had the opportunity to talk to you face to face, rather than being asked to explain my views in writing, I would have clarified the persisting confusion in less than 5 minutes. However, since that is not possible at the moment, I'll briefly respond to your comments as best as I can, although there is no guarantee that I would successfully explain the central point of my arguments. Anyway, I'll just give it a go. So, please note my below comments:

Dear Dr Assar,

(CJB): I am unable to assist you in your original inquiry. I am responding only because I would like to make sure that I correctly understand the apparent evolution in your thinking about the nature of the Chaldean dates.
In the past you have, more than vigorously, argued that these dates are representations of Babylonian astronomical dates made by some translator who was ignorant of the correct relationship between the Babylonian and Macedonian civil calendars in Seleucid times, which, in your view at that time, was already based on the Dios = Arahsamnu alignment which you have demonstrated for Parthian times.
=================

(FA): I'll summarise my views as follows:

(a)- I still maintain that the three years 67 SEB, 75 SEB, and 82 SEB in the three Chaldean dates are according to the astronomical calendar of Seleucid Babylonia the beginning of whose months was decided by "sighting of the first lunar crescent", i.e., either direct visual contact or prediction using Babylonian techniques.

(b)- The Macedonian portions of these same dates, that is Apellaios (in 67 SEB), Dios (in 75 SEB) and Xandikos (in 82 SEB), are not the months of the civil, astronomical, or whatever, Seleucid calendar of Babylonia (cf. below for further explanation).

(c)- In my view, the translator of the original Babylonian dates ignored the relationship between the Macedonian/Seleucid and Babylonian months at the time of translation because it was of little relevance to him and his mission in Babylon. He was simply interested in converting the original "difficult" Babylonian lunar dates to something useful/meaningful that he could take away and use in his work. There was no point in his converting some old lunar dates into a different local calendar to take with him home, or spending extra time transposing the Babylonian dates to Macedonian followed by conversion from the latter into his own calendar. So, he made a single conversion: Babylonian lunar dates to his own schematic calendar with predetermined month-lengths and fixed intercalary rules. The advantage with this calendar was that it acted like a stopwatch. It required no fixed era, first month, epoch of day, and its months were independent of the observation of the lunar crescent (or its predicted time). The user (Hipparchus) would choose an era, a first calendar month, an epoch for day, and then begin converting the "difficult" Babylonian lunar dates to his own schematic calendar. This meant that he could leave Babylon at the end of his stay, go anywhere in the world, and still be able to work out the exact number of days from a past astronomical event in Babylon to his own time. Hence his lack of interest in the relationship between the Babylonian and Macedonian months in Babylonia. What Hipparchus (or an equally competent astronomer) did was extremely simple. On his departure from home, he kept track of the number of elapsed days until he got to Babylon (= d1). He then added to this the number of days he spent talking to his Babylonian colleagues (perhaps originally through a translator), touring the city, etc. until the day he decided to convert the Babylonian dates (= d2). The total d1 + d2 enabled him to locate the day of the current month in his own calendar. Synchronising this with the corresponding Babylonian day, he requested the list of Babylonian month-lengths (i.e., tablets similar to the Lunar Text 39 etc.). Going through the Babylonian astronomical records (perhaps with the aid of an assistance) he picked the events he was interested in one by one. For each of them, he went back to the list of Babylonian month-lengths and counted from the day of translation backwards until he got to the day of the original observation (= d3). He then went back to his own calendar and counted backwards exactly the same number of days (= d3) until he got the days of his chosen Babylonian observations mapped into his own calendar one by one. That is it. His job was done. So, off he went with no fear of getting confused back home. I have never believed in an intermediary stage, involving conversion to a local (civil) Seleucid calendar, because it is simply unnecessary. It amounts to transposing the original Babylonian dates into two different calendars for no apparent reason. As for the era and first month of his schematic calendar, Hipparchus took Artemisios (almost) = Nisanu 311 BC because, Dios was, back in his country, roughly aligned with the Babylonian Tashritu. And, we have some clear evidence to show that Dios was indeed roughly aligned with Tashritu in Macedonia and Asia Minor (i.e., pre Granicus alignment). This is the gist of my arguments. And I have one of the Chaldean entries to show that its date is not according to a Babylonian type lunisolar calendar (whether with Babylonian or Macedonian month-names). It is a converted date and therefore slightly differs from the original Babylonian. One may argue that the apparent slight difference is due to the difference between the Seleucid civil and Babylonian lunisolar calendars. But I see no sense in Hipparchus taking the trouble to transpose the original Babylonian dates into the local Seleucid calendar (with its particular intercalary rules) and then from the latter to his own calendar with a different intercalary cycle. I am getting rid of this transitional stage because it simply defies logic. I believe Hipparchus mapped the original Babylonian lunar dates directly into his own calendar because he was a wise man. If he was a nut, then that is a different proposition I have no intention of considering.

(CJB): You held that this mis-translation was made long after the event and probably at some provincial site whence it came eventually to Ptolemy in Alexandria. If I understand you correctly, from this post and from your recent posts on the HASTRO-L list, it is now your view that the translation was actually made in Babylon after all, very possibly by Hipparchus himself but in any case by a non-Babylonian astronomer (though I am unclear what exactly you mean by "translation" because you objected when I inferred on HASTRO-L that you thought Hipparchus was able to read cuneiform or Aramaic).

(FA): I believe the apparent mis-translation, combining the Macedonian/Seleucid month-names with Seleucid years on the Babylonian rather than Macedonian count indicates that the three Chaldean dates do not represent the Babylonian-Macedonian month alignments in Babylonia. They are simply the months in the calendar of the translator. So, the translation either happened on the spot in Babylon (more likely - with Hipparchus being aided by a bilingual Babylonian, conversant in both Greek and the local tongue), or Hipparchus simply kept a record of the number of elapsed days for each of the past Babylonian astronomical observations, went back home and then mapped them into his own calendar (in either case he had no use for the Babylonian months of the original observations or their relation with those of the Seleucid civil calendar). I cannot decide for Hipparchus but personally believe that he converted the dates while still in Babylon to minimise error. If in doubt, he could have consulted the originals in Babylon whereas back home, he wouldn't have had the opportunity to do so.

(CJB): I also understand that you now think the translation is not just a misrepresentation of a Babylonian date but involved a conversion to an independent Macedonian astronomical calendar, one in which the epoch of the day was not at dusk, which had no epoch for the year, and no defined era, presumably adopting the SEB year for convenience. Does that correctly reflect your current position?

(FA): According to my calculations and contrary to Pliny's statement, the epoch of day in Hipparchus' astronomical calendar with Macedonian month names was not set at midnight for one of the converted observations. However, this depends on whether we accept the Babylonian observational methodology. We could shift the corresponding observation by a couple of hours and set the day's epoch at midnight. It won't affect the computations, but would contradict a Babylonian astronomical term (perhaps this is superfluous). As for the era and first month of Hipparchus' calendar, I have briefly explained my views above.

(CJB): Is it still your view that the Seleucid civil alignment was based on Dios = Arahsamnu in the third century and/or in Hipparchus' time? If so, how do you now explain the Dios = Tashritu alignment of these dates?
For the avoidance of doubt: I do not intend to debate the matter with you, in light of past experience. I only want to be sure I correctly understand your current position.

(FA): It is still my contention that the Seleucid calendar (whether civil or astronomical) operated Dios = Arahsamnu throughout the empire. The Parthians were not calendar makers. They simply inherited the Seleucid calendar from the Seleucids. If we accept Dios = Arahsamnu under the Parthians (I think the evidence is overwhelming), we should consider the same under the Seleucids (I have collected enough evidence to support this, going back to the Achaemenids and showing that their calendar in Egypt too was modelled on the Babylonian with exactly the same intercalary cycle (we have Aramaic intercalations) but with schematic months, etc.). As for the Dios (almost) = Tashritu alignment of the Chaldean dates, this simply concerns the relationship between the Babylonian lunar months and the calendar months of the translator, not the Babylonian months and those in the native Macedonian/Seleucid calendar of Babylonia. I believe Hipparchus had little interest in the latter. He was simply interested in the length of Babylonian months. A Babylonian to local Seleucid conversion would have required Hipparchus to take home some dates according to an alien calendar with its own regulatory rules instead of his own native calendar. That was not what he went to Babylon for. He visited the city simply to work out the total number of days from the time of some earlier Babylonian observations to his own day, regardless of the relationship between the months of local calendars. This is what I believe in but have no intention, whatsoever, of imposing it on anyone.

Dear Dr Assar,
I am unable to assist you in your original inquiry. I am responding only because I would like to make sure that I correctly understand the apparent evolution in your thinking about the nature of the Chaldean dates.
In the past you have, more than vigorously, argued that these dates are representations of Babylonian astronomical dates made by some translator who was ignorant of the correct relationship between the Babylonian and Macedonian civil calendars in Seleucid times, which, in your view at that time, was already based on the Dios = Arahsamnu alignment which you have demonstrated for Parthian times. You held that this mis-translation was made long after the event and probably at some provincial site whence it came eventually to Ptolemy in Alexandria.
If I understand you correctly, from this post and from your recent posts on the HASTRO-L list, it is now your view that the translation was actually made in Babylon after all, very possibly by Hipparchus himself but in any case by a non-Babylonian astronomer (though I am unclear what exactly you mean by "translation" because you objected when I inferred on HASTRO-L that you thought Hipparchus was able to read cuneiform or Aramaic). I also understand that you now think the translation is not just a misrepresentation of a Babylonian date but involved a conversion to an independent Macedonian astronomical calendar, one in which the epoch of the day was not at dusk, which had no epoch for the year, and no defined era, presumably adopting the SEB year for convenience. Does that correctly reflect your current position?
Is it still your view that the Seleucid civil alignment was based on Dios = Arahsamnu in the third century and/or in Hipparchus' time? If so, how do you now explain the Dios = Tashritu alignment of these dates?
For the avoidance of doubt: I do not intend to debate the matter with you, in light of past experience. I only want to be sure I correctly understand your current position.
Regards,
Chris Bennett

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[Non-text portions of this message have been removed]

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